171824-88-7Relevant articles and documents
cis-Pyridyl core-modified porphyrins for the synthesis of cationic water-soluble porphyrins and unsymmetrical non-covalent porphyrin arrays
Santra, Sangita,Kumaresan, Duraisamy,Agarwal, Neeraj,Ravikanth, Mangalampalli
, p. 2353 - 2362 (2003)
Synthesis of a series of 21-thia and 21-oxoporphyrin building blocks containing two pyridyl functional groups at the meso positions in a cis fashion is reported. The building blocks were used to synthesize a series of cationic water-soluble 21-thia and 21-oxoporphyrins. An unsymmetrical non-covalent trimer containing two dissimilar porphyrin cores such as one N3S and two N4 porphyrins cores was also constructed using the pyridyl porphyrin building blocks reported here.
Identification of Single-Atom Ni Site Active toward Electrochemical CO2Conversion to CO
Kim, Haesol,Shin, Dongyup,Yang, Woojin,Won, Da Hye,Oh, Hyung-Suk,Chung, Min Wook,Jeong, Donghyuk,Kim, Sun Hee,Chae, Keun Hwa,Ryu, Ji Yeon,Lee, Junseong,Cho, Sung June,Seo, Jiwon,Kim, Hyungjun,Choi, Chang Hyuck
, p. 925 - 933 (2021/02/03)
Electrocatalytic conversion of CO2 into value-added products offers a new paradigm for a sustainable carbon economy. For active CO2 electrolysis, the single-atom Ni catalyst has been proposed as promising from experiments, but an idealized Ni-N4 site shows an unfavorable energetics from theory, leading to many debates on the chemical nature responsible for high activity. To resolve this conundrum, here we investigated CO2 electrolysis of Ni sites with well-defined coordination, tetraphenylporphyrin (N4-TPP) and 21-oxatetraphenylporphyrin (N3O-TPP). Advanced spectroscopic and computational studies revealed that the broken ligand-field symmetry is the key for active CO2 electrolysis, which subordinates an increase in the Ni redox potential yielding NiI. Along with their importance in activity, ligand-field symmetry and strength are directly related to the stability of the Ni center. This suggests the next quest for an activity-stability map in the domain of ligand-field strength, toward a rational ligand-field engineering of single-atom Ni catalysts for efficient CO2 electrolysis.
Nickel complexes of 21-oxaporphyrin and 21,23-dioxaporphyrin
Chmielewski, Piotr J.,Latos-Grazynski, Lechoslaw,Olmstead, Marilyn M.,Balch, Alan L.
, p. 268 - 278 (2007/10/03)
The nickel(1) and nickel(11) complexes of 5,20-bis(p-tolyl)-10,15-diphenyl-21-oxaporphyrin (ODTDPPH) and 5,10,15,20-tetraphenyl-21,23-dioxaporphyrin (O2TPP) have been investigated. These oxa analogues of 5,10,15,20-tetraarylporphyrin, where one or two pyrrole rings are replaced by a furan moiety, have been synthesized by condensation of the respective precursors, namely 2,5-bis(arylhydroxymethyl) furan, pyrrole, and arylaldehyde. Insertion of nickel(11) into ODTDPPH or O2TPP yielded high-spin five- and six-coordinate ([(ODTDPP)Ni11Cl] and [(O2TPP)Ni11Cl2]) complexes, which can be reduced with moderate reducing reagents. The EPR spectra of[(ODTDPP)Ni1] and [(O2TPP)Ni1Cl] revealed the Ni1 oxa(dioxa)porphyrin rather than a Ni11 anion radical electronic structure. In the structures of [(ODTDPP)Ni11Cl], [(O2TPP)Ni11Cl2], and [(ODTDPP)Ni1], determined by X-ray diffraction, the furan ring is planar and coordinates in the n1 fashion through the trigonal oxygen atom; the nickel ion lies in the furan plane for the latter two complexes, but slightly outside it in [(ODTDPP)Ni11Cl]. The Ni N and Ni O bond lengths decrease upon reduction of high-spin five-coordinate [(ODTDPP)Ni11Cl] to four-coordinate [(ODTDPP)Ni1]. The pattern of downfield pyrrole resonances in 1H NMR spectra of [(ODTDPP)Ni11Cl] and [(O2TPP)-Ni11Cl2] has been established. The downfield positions of furan resonances are unusual for Ni11 heteroporphyrins; they have been accounted for by the nearly in-plane coordination of the furan moiety as opposed to the side-on coordination found for thiophene- or selenophene-containing heteroporphyrins. An example of ion-pair formation, [(O2TPPH)2][Ni11Cl4], was produced from [(O2TPP)Ni11Cl2] by acidification with HCl.
